Follow-up of anti-Aspergillus IgG and IgA antibodies in bone marrow transplanted patients with invasive aspergillosis

Retrospective Comparison of Two Aspergillus IgG Enzyme Immunoassays for Diagnosing Pulmonary Aspergillosis

Aspergillus-specific antibodies are diagnostic indicators of allergic bronchopulmonary aspergillosis (ABPA) and chronic pulmonary aspergillosis (CPA). Tests for detecting Aspergillus-specific antibodies were not used clinically in Japan, and the production of the Aspergillus precipitin test was discontinued. Thus, alternative tests for diagnosing aspergillosis are urgently needed. We retrospectively evaluated 64 patients with suspected ABPA and CPA who underwent precipitin antibody testing. Serum Aspergillus IgG levels were measured and compared using the Bordier Aspergillus fumigatus ELISA and the Platelia Aspergillus IgG (Bio-Rad) kits. Of the participants, 18 were diagnosed with CPA, and 8 were diagnosed with ABPA. Both the Bordier and Bio-Rad kits showed high sensitivity and specificity for CPA and ABPA. The area under the receiver operating characteristic curves for the Bordier and Bio-Rad kits were 0.97 and 0.95, respectively, for CPA, and 0.89 and 0.91, respectively, for ABPA. In contrast to the Bordier kit, the Bio-Rad kit showed relatively low anti-Aspergillus IgG levels and lower sensitivity to non-fumigatus Aspergillus infections. The Aspergillus-specific IgG ELISA tests showed sufficient diagnostic accuracy. Therefore, these assays are recommended as alternatives to the precipitin kit for diagnosing aspergillosis in clinical settings in Japan.

COVID-19-associated pulmonary aspergillosis in a tertiary care center in Shenzhen City

Objectives

The severe coronavirus disease 2019 (COVID-19) is characterized by acute respiratory distress syndrome (ARDS) and risk of fungal co-infection, pulmonary aspergillosis in particular. However, COVID-19 associated pulmonary aspergillosis (CAPA) cases remain limited due to the difficulty in diagnosis.

Methods

We describe presumptive invasive aspergillosis in eight patients diagnosed with COVID-19 in a single center in Shenzhen, China. Data collected include underlying conditions, mycological findings, immunodetection results, therapies and outcomes.

Results

Four of the eight patients had tested positive for Aspergillus by either culture or Next-generation sequencing analysis of sputum or bronchoalveolar lavage fluid (BALF), while the rest of patients had only positive results in antigen or antibody detection. Although all patients received antifungal therapies, six of these eight patients (66.7%) died.

Conclusion

Due to the high mortality rate of CAPA, clinical care in patients with CAPA deserves more attention.

Evaluation of Aspergillus IgG, IgM antibody for diagnosing in chronic pulmonary aspergillosis: A prospective study from a single center in China

Chronic pulmonary aspergillosis (CPA) is a slowly progressing pulmonary fungal infectious disease caused by Aspergillus. Aspergillus IgG, IgM are now considered to be valuable biomarkers in CPA diagnosing.Our research attempts to evaluate the effectiveness of Aspergillus IgG, IgM in diagnosing CPA.In our study, CPA patients were younger than the patients who suffered other pulmonary disease. The most common underlying disease in CPA patients was pulmonary tuberculosis. And the most common clinical symptom was hemoptysis. The comparison among the groups indicated statistical significance with regard to Aspergillus IgG and IgM between the CPA and other pulmonary disease groups (P < .01). The Aspergillus-specific IgG and IgM in infectious group exhibited higher levels than those in colonization group (P < .01). The area under the receiver operating characteristic curve of Aspergillus IgG was 0.762 (95% confidence interval: 0.664-0.860) (P < .01).Aspergillus-specific IgG offers great diagnostic value with regard to CPA.

Should all tubercular cavities be left alone? Lessons from a heart transplant

Fungal infection after solid organ transplantation poses a diagnostic and therapeutic challenge. We present the case of a 50-year-old man who underwent orthotopic heart transplantation for dilated cardiomyopathy with a history of treated pulmonary tuberculosis 10 years pre-transplant. One year post-transplantation, he was admitted with recurrent productive cough and was evaluated to have intracavitory aspergillosis of the lung. He was started on medical therapy with reduction in immunosuppression, but succumbed later with allograft rejection and multiorgan failure. Management of invasive aspergillosis in immunocompromised host is a real challenge. Management protocol should be individualised.

Diagnostic value of serum galactomannan, (1,3)-β-d-glucan, and Aspergillus fumigatus-specific IgA and IgG assays for invasive pulmonary aspergillosis in non-neutropenic patients

Detection of serum galactomannan (GM) and (1,3)-β-d-glucan (BG) is considered useful for non-culture diagnosis of invasive pulmonary aspergillosis (IPA) in neutropenic patients. Only few studies evaluated these seromarkers in non-neutropenic patients suspected of having IPA. The aim of this study was to evaluate both tests together with the Aspergillus fumigatus-specific serum IgG and IgA (IgAG) test for serological IPA diagnosis in non-neutropenic patients. Sera from 87 patients suspected of having IPA were retrospectively analysed. Patients were categorised into groups of proven IPA (n = 10), putative IPA (n = 31) and non-IPA colonisation (n = 46). When the GM, BG and IgAG assays were used for patients included in the study, the sensitivity/specificity/positive predictive value (PPV)/negative predictive value (NPV) were 48.8%/91.3%/83.3%/66.7%, 82.9%/73.9%/73.9%/82.9% and 75.6%/95.7%/93.9%/81.5%, respectively. Thus, the highest specificity and PPV were confirmed for the IgAG assay. Improvements in the sensitivity and NPV were achieved by "at least one positive" analysis with the GM and BG assays, with the sensitivity/specificity/PPV/NPV values being 85.0%/69.6%/71.4%/84.2%. Nevertheless, the highest sensitivity and NPV were achieved by the "at least one positive" analysis combining the GM, BG and IgAG tests (97.6% and 96.8%, respectively). The involvement of the IgAG assay could improve IPA diagnosis in non-neutropenic patients by increasing the sensitivity and NPV when combined with the GM or BG assays. Furthermore, improvement was achieved by combining the GM, BG and IgAG assays using the "at least one positive test" strategy, especially if doubt exists.

Oxidative responses and fungal infection biology

The balance between reactive oxygen species and reactive nitrogen species production by the host and stress response by fungi is a key axis of the host-pathogen interaction. This review will describe emerging themes in fungal pathogenesis underpinning this axis.

Aspergillus serology: Have we arrived yet?

Aspergillosis presents in various clinical forms, among them chronic pulmonary aspergillosis, which is a spectrum of disease entities including aspergilloma, chronic cavitary pulmonary aspergillosis, and chronic fibrosing pulmonary aspergillosis. Aspergillus also contributes to fungal allergy and sensitization. Analysis of the immune response to Aspergillus and its antigens is an integral part of the diagnosis of these diseases. Over the past half century, the techniques used to determine antibody titers have evolved from testing for precipitating and agglutinating antibodies by agar gel double diffusion and immunolectrophoresis to enzyme-linked immunosorbent assays using recombinant proteins as capture antigens. A resurgence of interest in the detection of immunoglobulins, primarily Aspergillus-specific IgG, has hinted at the possibility of distinguishing between colonization and invasion in immunocompromised patients with invasive aspergillosis. Even though there appears to be a greater degree of discrimination between the clinical forms of aspergillosis there is still a long way to travel. This review presents illustrative examples of where new diagnostic platforms and technologies have been applied to this intriguing spectrum of diseases.

Proteomic Profiling of Serological Responses to Aspergillus fumigatus Antigens in Patients with Invasive Aspergillosis

Aspergillus fumigatus is the species that most commonly causes the opportunistic infection invasive aspergillosis (IA) in patients being treated for hematological malignancies. Little is known about the A. fumigatus proteins that trigger the production of Aspergillus-specific IgG antibodies during the course of IA. To characterize the serological response to A. fumigatus protein antigens, mycelial proteins were separated by 2-D gel electrophoresis. The gels were immunoblotted with sera from patients with probable and proven IA and control patients without IA. We identified 49 different fungal proteins, which gave a positive IgG antibody signal. Most of these antigens play a role in primary metabolism and stress responses. Overall, our analysis identified 18 novel protein antigens from A. fumigatus. To determine whether these antigens can be used as diagnostic or prognostic markers or exhibit a protective activity, we employed supervised machine learning with decision trees. We identified two candidates for further analysis, the protein antigens CpcB and Shm2. Heterologously produced Shm2 induced a strongly proinflammatory response in human peripheral blood mononuclear cells after in vitro stimulation. In contrast, CpcB did not activate the immune response of PBMCs. These findings could serve as the basis for the development of an immunotherapy of IA.

Antibody testing in aspergillosis--quo vadis?

Humans are constantly exposed to airborne Aspergillus spores. Most develop Aspergillus-specific antibodies by adulthood. Persons with chronic lung disease or Aspergillus airway colonization often have raised levels of Aspergillus-specific immunoglobululin G (IgG). It is not known whether this signifies an increased risk of future aspergillosis.Chronic and allergic forms of pulmonary aspergillosis are estimated to affect over three million people worldwide. Antibody testing is central to diagnosis of these conditions, with raised Aspergillus-specific IgG in chronic pulmonary aspergillosis and raised Aspergillus-specific IgE in allergic aspergillosis. Antibody levels are also used to monitor treatment response in these syndromes. Acute invasive disease is less common. There is a more limited role for antibody testing in this setting as immunosuppression often results in delayed or absent antibody response.Many methods exist to detect Aspergillus-specific antibodies, but there are limited published data regarding comparative efficacy and reproducibility. We discuss the comparative merits of the available tests in the various clinical settings and their suitability for use in the resource-poor settings where the majority of cases of aspergillosis are thought to occur. We summarize the gaps in existing knowledge and opportunities for further study that could allow optimal use of antibody testing in this field.

Galactomannan antigen detection in the diagnosis of invasive aspergillosis

Invasive aspergillosis is a serious and lethal infection among immunocompromised patients, with reported mortality rates as high as 74-92%. The high mortality is related to the severe immunosuppression experienced by these patients as well as the difficulties for physicians in arriving at a timely diagnosis. Definitive diagnostic procedures (tissue biopsy for histopathology and culture) are often precluded by severe cytopenias and coagulation abnormalities. The development of minimally invasive, nonculture diagnostic methods is a major advance in the early diagnosis of invasive aspergillosis. Galactomannan is a heteropolysaccharide (mannan core and side residues of galactofuranosyl units) present in the cell wall of Aspergillus spp. The double sandwich enzyme immunoassay, which detects galactomannan in serum samples, has been available in Europe for almost a decade and in the USA since May 2003, for the diagnosis of invasive aspergillosis. However, availability of the double galactomannan enzyme immunoassay is center variable in the USA and, although its analytical performance in the diagnosis of invasive aspergillosis is well documented, its routine use in clinical practice is limited. As an adjunct in the diagnosis and management of invasive aspergillosis, incorporation of the galactomannan enzyme immunoassay into clinical trials will help to further define its role.

Acute Aspergillus pneumonia associated with mouldy tree bark-chippings, complicated by anti-glomerular basement membrane disease causing permanent renal failure

A non-immunocompromised man developed acute Aspergillus pneumonia after spreading mouldy tree bark mulch. Despite normal renal function at presentation, he developed rapidly progressive glomerulonephritis with acute kidney injury due to anti-glomerular basement membrane antibodies (anti-GBM) 4 weeks later. He remained dialysis dependent and died of sepsis 10 months later. We hypothesise that he contracted invasive pulmonary Aspergillosis from heavy exposure to fungal spores, leading to epitope exposure in the alveoli with subsequent development of GBM auto-antibodies.

Aspergillus spondylodiscitis in solid organ transplant recipients

BACKGROUND

Transplantation practices have had a significant effect on the epidemiology of invasive Aspergillosis. Aspergillus spondylodiscitis is rare in transplant recipients. The optimal treatment has yet to be defined because of the rarity of such cases. This article reviews the available literature on Aspergillus spondylodiscitis in solid organ transplant recipients and provides recommendations on its management.

METHODS

We identified 15 cases of Aspergillus spondylodiscitis in transplant recipients. Most patients were heart transplant recipients. Back pain was the mode of presentation in all patients. Most cases were afebrile. The dominant location was the lumbar spine.

RESULTS

Aspergillus fumigatus was responsible for 84.62% of cases and A flavus for 15.38%. The overall recovery rate was 66.67%. Delay in diagnosis remained a major impediment to the successful treatment of spinal aspergillosis. Treatment included antifungal therapy alone or combined with surgery. Initial therapy with voriconazole could lead to better curative effects.

CONCLUSION

Combined medical and operative interventions are recommended for treatment.

Aspergillus lung disease in patients with sarcoidosis: a case series and review of the literature

Chronic cavitary pulmonary aspergillosis (CCPA) has been associated with advanced lung diseases. Pulmonary sarcoidosis, a granulomatous inflammatory disorder, is associated with CCPA. We identified CCPA in 2% of cases in a large cohort of sarcoidosis patients. We found a lack of response to medical treatment and poor outcome in this subgroup.

Animal models: an important tool in mycology

Animal models of fungal infections are, and will remain, a key tool in the advancement of the medical mycology. Many different types of animal models of fungal infection have been developed, with murine models the most frequently used, for studies of pathogenesis, virulence, immunology, diagnosis, and therapy. The ability to control numerous variables in performing the model allows us to mimic human disease states and quantitatively monitor the course of the disease. However, no single model can answer all questions and different animal species or different routes of infection can show somewhat different results. Thus, the choice of which animal model to use must be made carefully, addressing issues of the type of human disease to mimic, the parameters to follow and collection of the appropriate data to answer those questions being asked. This review addresses a variety of uses for animal models in medical mycology. It focuses on the most clinically important diseases affecting humans and cites various examples of the different types of studies that have been performed. Overall, animal models of fungal infection will continue to be valuable tools in addressing questions concerning fungal infections and contribute to our deeper understanding of how these infections occur, progress and can be controlled and eliminated.

Pulmonary complications following hematopoietic stem cell transplantation: diagnostic approaches

Pulmonary complications are a significant cause of morbidity and mortality in hematopoietic stem cell transplant recipients. Pulmonary infiltrates in such patients pose a major challenge for clinicians because of the wide differential diagnosis of infectious and noninfectious conditions. It is rare for the diagnosis to be made by chest radiograph, and commonly these patients will need further invasive and noninvasive studies to confirm the etiology of the pulmonary infiltrates. This review describes the role of the different diagnostic tools available to reach a diagnosis in a timely manner in this patient population.

Laboratory diagnosis of invasive aspergillosis

Invasive aspergillosis occurs in a wide range of clinical scenarios, is protean in its manifestations, and is still associated with an unacceptably high mortality rate. Early diagnosis is critical to a favourable outcome, but is difficult to achieve with current methods. Deep tissue diagnostic specimens are often difficult to obtain from critically ill patients. Newer antifungal agents exhibit differential mould activity, thus increasing the importance of establishing a specific diagnosis of invasive aspergillosis. For these reasons, a range of alternate diagnostic strategies have been investigated. Most investigative efforts have focused on molecular and serological diagnostic techniques. The detection of metabolites produced by Aspergillus spp and a range of aspergillus-specific antibodies represent additional, but relatively underused, diagnostic avenues. The detection of galactomannan has been incorporated into diagnostic criteria for invasive aspergillosis, reflecting an increased understanding of the performance, utility, and limitations of this technique. Measurement of (1,3)-beta-D glucan in blood may be useful as a preliminary screening tool for invasive aspergillosis, despite the fact that this antigen can be detected in a number of other fungi. There have been extensive efforts directed toward the detection of Aspergillus spp DNA, but a lack of technical standardisation and relatively poor understanding of DNA release and kinetics continues to hamper the broad applicability of this technique. This review considers the application, utility, and limitations of the currently available and investigational diagnostic modalities for invasive aspergillosis.

Genes and molecules involved in Aspergillus fumigatus virulence

Aspergillus fumigatus causes a wide range of diseases that include mycotoxicosis, allergic reactions and systemic diseases (invasive aspergillosis) with high mortality rates. Pathogenicity depends on immune status of patients and fungal strain. There is no unique essential virulence factor for development of this fungus in the patient and its virulence appears to be under polygenetic control. The group of molecules and genes associated with the virulence of this fungus includes many cell wall components, such as beta-(1-3)-glucan, galactomannan, galactomannanproteins (Afmp1 and Afmp2), and the chitin synthetases (Chs; chsE and chsG), as well as others. Some genes and molecules have been implicated in evasion from the immune response, such as the rodlets layer (rodA/hyp1 gene) and the conidial melanin-DHN (pksP/alb1 gene). The detoxifying systems for Reactive Oxygen Species (ROS) by catalases (Cat1p and Cat2p) and superoxide dismutases (MnSOD and Cu, ZnSOD), had also been pointed out as essential for virulence. In addition, this fungus produces toxins (14 kDa diffusible substance from conidia, fumigaclavin C, aurasperon C, gliotoxin, helvolic acid, fumagilin, Asp-hemolysin, and ribotoxin Asp fI/mitogilin F/restrictocin), allergens (Asp f1 to Asp f23), and enzymatic proteins as alkaline serin proteases (Alp and Alp2), metalloproteases (Mep), aspartic proteases (Pep and Pep2), dipeptidyl-peptidases (DppIV and DppV), phospholipase C and phospholipase B (Plb1 and Plb2). These toxic substances and enzymes seems to be additive and/or synergistic, decreasing the survival rates of the infected animals due to their direct action on cells or supporting microbial invasion during infection. Adaptation ability to different trophic situations is an essential attribute of most pathogens. To maintain its virulence attributes A. fumigatus requires iron obtaining by hydroxamate type siderophores (ornitin monooxigenase/SidA), phosphorous obtaining (fos1, fos2, and fos3), signal transductional falls that regulate morphogenesis and/or usage of nutrients as nitrogen (rasA, rasB, rhbA), mitogen activated kinases (sakA codified MAP-kinase), AMPc-Pka signal transductional route, as well as others. In addition, they seem to be essential in this field the amino acid biosynthesis (cpcA and homoaconitase/lysF), the activation and expression of some genes at 37 degrees C (Hsp1/Asp f12, cgrA), some molecules and genes that maintain cellular viability (smcA, Prp8, anexins), etc. Conversely, knowledge about relationship between pathogen and immune response of the host has been improved, opening new research possibilities. The involvement of non-professional cells (endothelial, and tracheal and alveolar epithelial cells) and professional cells (natural killer or NK, and dendritic cells) in infection has been also observed. Pathogen Associated Molecular Patterns (PAMP) and Patterns Recognizing Receptors (PRR; as Toll like receptors TLR-2 and TLR-4) could influence inflammatory response and dominant cytokine profile, and consequently Th response to infec tion. Superficial components of fungus and host cell surface receptors driving these phenomena are still unknown, although some molecules already associated with its virulence could also be involved. Sequencing of A. fumigatus genome and study of gene expression during their infective process by using DNA microarray and biochips, promises to improve the knowledge of virulence of this fungus.

Aspergillus infections in transplant recipients

Aspergillus infections are occurring with an increasing frequency in transplant recipients. Notable changes in the epidemiologic characteristics of this infection have occurred; these include a change in risk factors and later onset of infection. Management of invasive aspergillosis continues to be challenging, and the mortality rate, despite the use of newer antifungal agents, remains unacceptably high. Performing molecular studies to discern new targets for antifungal activity, identifying signaling pathways that may be amenable to immunologic interventions, assessing combination regimens of antifungal agents or combining antifungal agents with modulation of the host defense mechanisms, and devising diagnostic assays that can rapidly and reliably diagnose infections represent areas for future investigations that may lead to further improvement in outcomes.